1. Field of the Invention
This invention relates to an improvement for in-line or conventional roller skate wheels, more particularly structures which improve tire stiffness, permit ready tire changes to accommodate different skating conditions, prolong tire life and reduce complexity.
2. Description of the Prior Art
Conventional roller skating has enjoyed considerable popularity for decades if not centuries. Although in-line roller skates are not novel, interest in them did not eclipse that in conventional skates until technological advances gave skaters greater capability on them in the last decade.
A conventional wheel used for in-line skating consists of a thermoset urethane tire molded on or about a single or split flanged hub. Urethane is inherently soft and malleable. When a skater turns or exerts force lateral to the rotational plane of the tire, the tire bends. In addition to the heat caused by friction which the tire experiences, repeated bending causes a weakening of the tire material and eventually leads to failure. From a performance aspect, skaters not only lose speed due to energy dissipation, but also the ability to precisely control the their movement. Prior inventors have addressed these vexing problems, but none have resolved them as fully as the present invention.
In-line skating has evolved into many different performance specialties, not unlike those of ice skating. Some fast-evolving areas include: hockey, speed skating, trick skating and touring. Each specialty area imposes different demands on skaters' tires which are better met by different tire designs. Additionally, many skaters may perform better with tread designs, not unlike on automobile tires, which are more suited to inclement weather or other conditions. Because skaters should not be resigned to only one type of activity or weather condition, skaters should be able rapidly to fit their skates with tires appropriate for each type of activity or circumstance in which they skate. Prior inventions do not address this problem at all.
U.S. Pat. No. 180,646 issued Aug. 1, 1876 to C. W. Saladee describes a wheel assembly which comprises dual hubs which capture and compresses the tire, and a bearing set. Saladee's invention does not include a tire stiffened with a rib, or a hub structure designed to positively restrict lateral displacement of the tire under great lateral stress. Saladee's wheel assembly also includes only one set of bearings whereas the instant invention has two to better withstand these aforementioned tremendous lateral forces.
U.S. Pat. No. 687,721 issued Dec. 3, 1901 to T. W. Bryant describes a wheel assembly which comprises dual hubs which capture a simple toroidal tire and which form the races for two sets of bearings. First, Bryant's design does not take advantage of the speed enhancing properties of precision bearings which are included in the instant invention. Second, Bryant's invention involves spacers between the hubs which have been eliminated in the instant invention. Finally, Bryant's tire is not stiffened by a rib or restrained by a hub flange which deters tire slippage due to lateral forces.
U.S. Pat. No. 1,983,869 issued Dec. 11, 1934 to R. M. Nichol describes a skate wheel assembly which comprises dual hubs which capture a toroidal tire and which ride on the outer surface of a singular bearing package mounted on an axle. Nichol's design suffers some of the same difficulties as the above inventions and, due to the high walls formed on both outside edges of the tire, lacks the ability to accommodate severe turns which are commonplace to modern in-line skating.
U.S. Pat. No. 4,666,169 issued May 19, 1987 to S. Hamill et al. describes a wheel assembly comprising a tire molded onto a single hub and encapsulating a cross-shaped rib. Hamill's invention fails to incorporate the tire with a hub having flanges hub oblique to the wheel assembly's rotational axis which would support the tire during maneuvers when the great force is applied to the tire at non-perpendicular angles to the axle. The present invention provides this support, thereby improving the life and stability of the tire. The rib Hamill discloses also includes circumferential protuberances. The present invention has no circumferential protuberances, rather radially diverged bores through which tire material may be cast thereby affording even greater stability. Hamill's rib is further limited to being incorporated within a singular hub, rather than being part of the tire both of which being sandwiched by dual, symmetrical hubs.
The present invention provides significant advances over Hamill's invention: First, the user may employ different tire/rib assemblies with the same hubs and bearing assemblies; the user will not be forced to purchase multiple bearing and hub sets with each tire selection, rather only the tire/rib assemblies the user needs. Second, although Hamill's invention is purposed at stabilizing the tire, it is shown extending only part way through the tire. Hamill's tire will be less axially deformable than without a rib, but not nearly as stiff as in the present invention which extends the rib nearly to the tread. More importantly, Hamill's invention fails to address radial deformation of the tire while skating. Radial deformation operates to dissipate rolling momentum and slows a skater down or reduces the skaters' gliding ability. The present invention provides a rib extending through practically the entire length of the tire leaving little material between the rib and the skating surface, thereby allowing little deformation and improving performance.
U.S. Pat. No. 5,308,152 issued May 3, 1994 to D. Ho describes two types of wheel assemblies which both comprise dual hubs which capture the tire along with a singular bearing package: (1) in which the tire is shaped to accommodate a stepped configuration matching the hub; and (2) in which the tire encapsulates a radial, tangential, t-shaped resilient member along the inner circumference of the tire. Ho's hub design fails to permit hub interchangeability as the instant invention does by incorporating alternatingly tapped and untapped holes for accommodating the head or threaded portion of the fastener used to hold the assembly together. Ho's stepped-hub design also does not take advantage of a smooth interface between tire and hub which the instant invention utilizes so that when skaters make severe turns, the forces against the side of the tire are normal to a smooth hub wall holding the tire in place; Ho's stepped configuration introduces stress nodes which may cause premature failure of the tire. Finally, Ho's t-shaped encapsulated member may serve to hold the tire in place, but does not provide tire outer edge stiffness that the instant invention provides which better resists the lateral forces imposed on the tire and permits skaters to employ thinner tires with less resistance.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.